Summary of Work: Airway mucin hypersecretion is associated with a variety of diseases characterized by airway inflammation, such as asthma, chronic bronchitis, and cystic fibrosis. In these disease states, excessive airway secretion is a cause of morbidity. Human airway epithelial cells express at least 7 mucin genes. The relative contribution of each of these gene products to airway hypersecretion is unknown at present. In order to measure secreted products of individual genes in vitro and in airway secretions, fusion proteins containing unique nonglycosylated epitopes from mucin genes expressed in the airway have been produced and used to raise antisera specific for individual gene products. Creation of enzyme-linked immunoassays will allow for the assay of mucin gene-specific products in culture media from in vitro experiments or in airway secretions.